Combined Binder Research Articles

ALTERNATIVE BINDERS TO BENTONITE FOR IRON ORE PELLETIZING: PART I: EFFECTS ON PHYSICAL AND MECHANICAL PROPERTIES

The use of conventional bentonite binder is favorable in terms of mechanical and metallurgical pellet properties, however, because of its acid constituents bentonite is considered as impurity especially for iron ores with high acidic content. Therefore, alternative binders to bentonite have been tested. Organic binders are the most studied binders and they yield pellets with good wet strength; they fail in terms of preheated and fired pellet strengths. This study was conducted to investigate how insufficient pellet strengths can be improved when organic binders are used as binder. The addition of a low-melting temperature and slag bonding/strength increasing constituent (free in acidic contents) into pellet feed was proposed. Addition of boron compounds such as colemanite, tincal, borax pentahydrate, boric acid together with organic binders such as CMC, starch, dextrin and some organic based binders, into iron oxide pellet was tested. Wet and thermally treated pellet physical-mechanical qualities (balling - moisture content - size - shape - drop number - compressive strengths - porosity - dustiness) were determined. The results showed that good quality wet, dry, preheated and fired pellets can be produced with combined binders (an organic binder plus a boron compound) when compared with bentonite-bonded pellets. While organic binders provided sufficient wet and dry pellet strengths, the boron compounds provided the required preheated and fired pellet strengths at even lower firing temperature. Especially, the contribution of boron compound addition is most pronounced for hematite pellets which do not have strengthening mechanism through oxidation like magnetite pellets during firing. Therefore, addition of boron compound is beneficial to recover the low physical-mechanical qualities of pellets produced with organic binders through slag bonding mechanism. Furthermore, lowering the firing temperature thanks to low-melting boron compounds will be cost-effective for firing part of the pelletizing plants.

Weathering indicator for artificial and natural weathering of wood coatings

The aim of the present study was to find and develop a sensor to evaluate the weathering rates of wood coatings during natural and artificial weathering using a material of known and controlled rate of decomposition. This was achieved by the use of a coating based on poly (vinyl acetate) copolymer binder in combination with Fe2+ as redox catalyst. It was possible to model the decomposition rates by dry film thickness, Fe2+ concentration and addition of pigments. One application of this sensor for wood coatings is to indicate the need of maintenance.

Formulation effects on the release of silica dioxide nanoparticles from paint debris to water

Waterborne paints with integrated nanoparticles have been recently introduced into the market as nanoparticles offer improved or novel functionalities to paints. However, the release of nanoparticles during the life cycle of nano-enhanced paint has only been studied to a very limited extent. The paint composition could determine in what quantities and forms the nanoparticles are released. In this work, paint formulations containing the same amount of silicon dioxide (SiO2) nanoparticles but differing in the pigment volume concentration (PVC) and in amount and type of binder and pigment, were studied through leaching test to investigate the influence of these parameters on release of Si from paint. The results indicate greater release of Si, about 1.7wt.% of the SiO2 nanoparticles in the paint, for paint formulated with higher PVC value (63%), suggesting that the PVC is a crucial factor for release of SiO2 nanoparticles from paints. This hypothesis was also based on the fact that agglomerates of SiO2 nanoparticles were only found in leachates from paint with higher PVC. A paint sample with the higher amount of binder and less calcite filler exhibited a lower release of Si among the paints with a low PVC value (35%), and no SiO2 particles were detected in leachates collected from this paint. This could be due to the fact that a high portion of binder forms a suitable matrix to hold the SiO2 ENPs in paint. The paint sample in which the amount of calcite was partially substituted with TiO2 pigment did not show an important reduction on Si release. Our work suggests that paint debris containing SiO2 nanoparticles may release a limited amount of Si into the environment, and that by adjusting the properties of the binder in combination with common pigments it is possible to reduce the release of SiO2 nanoparticles.

Image-analytical evaluation of the spatial distribution of particulate fillers in ceramic composites prepared via the polymer-derived ceramics route

A robust and versatile image analysis routine is presented for the quantitative evaluation of the spatial distribution of a recently developed ceramic composite system prepared by using preceramic polymers as both low-loss binder and reagent in combination with particulate fillers, yielding particulate zirconia-strengthened mullite. Micrographs of polished cross-sections were used as a base for binarization, noise-reduction and Voronoi-based tessellation operations, employing open-source software. The resulting cell area distributions were used to evaluate the microstructural homogeneity by calculating a defined factor of homogeneity. Furthermore, the skewness of the cell area distributions was introduced as a novel characteristic number for the characterization of the filler distribution. The resulting values of the experimentally determined microstructural descriptors were compared to values calculated from theoretical distributions following a Poisson Voronoi model, including a hard-core model approach, to determine the quality of spatial dispersion. Significant differences in the spatial distribution of zirconia particulates in the mullite matrix were found depending on the method of introduction of fillers into the precursor material, spray-coating being identified as the superior compounding method. The comparison to a conventional nearest-neighbor metric demonstrates the potential of the developed tessellation-based image-analysis routine, yielding additional information about the nature of the microstructural setup of the material.

Development and study of combined phenol-rubber binders for frictional composites

The paper reports the results of the development of combined phenol-rubber binders for the frictional composites containing resol phenol formaldehyde resin and synthetic butadiene nitrile rubber with various contents of acryl nitrile links. The effect of the method of production of the combined binder on its structure and properties is studied. The results of an investigation of the influence of the binder composition on properties of the frictional composites are presented. The structural transformations that occur during the preparation of the combined binders are studied.

Effect of modified elastomeric binders on the electrochemical properties of silicon anodes for lithium-ion batteries

Silicon has been investigated intensively as a promising anode material for rechargeable lithium-ion batteries. The choice of a binder is very important to solve the problem of the large capacity fade observed along cycling. The effect of modified elastomeric binders on the electrochemical performance of crystalline nano-silicon powders was studied. Compared with the conventional binder (polyvinylidene fluoride (PVDF)), Si electrodes using the elastomeric styrene butadiene rubber (SBR) and sodium carboxymethyl cellulose (SCMC) combined binder show an improved cycling performance. The reversible capacity of the Si electrode with the SCMC/SBR binder is as high as 2221 mA·h/g for 30 cycles in a voltage window between 0.005 and 2 V. The structure changes from SEM images of the silicon electrodes with different binders were used to explore the property improvement.

Designed protein binders in combination with nanocrystalline diamond for use in high-sensitivity biosensors

A platform for diagnostic applications showing signal-to-noise ratios that by far surpass those of traditional bioanalytical test formats has been developed. It combines the properties of modified nanocrystalline diamond (NCD) surfaces and those of polyethylene oxide and polypropylene oxide based block copolymers for surface passivation and binder conjugation with a new class of synthetic binders for proteins. The NCD surfaces were fluorine-, hydrogen-, or oxygen-terminated prior to further biofunctionalization and the surface composition was characterized by X-ray photoelectron spectroscopy. In a proof of principle demonstration targeting the C-reactive protein, an ELISA carried out using an F-terminated diamond surface showed a signal-to-noise ratio of 3,900 which compares well to the signal-to-noise of 89 obtained in an antibody-based ELISA on a polystyrene microtiter plate, a standard test format used in most life science laboratories today. The increase in signal-to-noise ratio is to a large extent the result of extremely efficient passivation of the diamond surface. The results suggest that significant improvements can be obtained in standardized test formats using new materials in combination with new types of chemical coatings and receptor molecules.

Pulse Electric Fields for EPD of Thermal Barrier Coatings

Conventional electrophoretic deposition is being combined with pulse electric fields to deposit yttria stabilized zirconia from ethanol based suspensions onto bondcoated turbine alloys for thermal barrier coatings. The addition of the pulse electric fields to the electrophoretic process has demonstrated the capability to decrease the coating roughness, minimize hydrolysis, and decrease coating edge effects commonly encountered in electrokinetic and electrochemical deposition processes. Subsequent to the electrophoretic deposition process the green body coatings were subjected to a combined binder burnout and sintering process for further coating densification. The coatings have been qualified in terms of surface roughness as well as microstructure and experiments have been performed to show that the pulse EPD process can deposit TBC materials onto turbine components.

Macroporous gibbsite foams prepared from particle-stabilized emulsions using corn starch and agar as binders

Corn starch and agar were used independently as a water-uptake binder in combination with anionic sodium dodecul sulfate (SDS) which modifies the hydrophobicity of cationic gibbsite platelets for preparation of air-in-water (a/w) gibbsite foams via a simple mechanical frothing. Contact-angle (θ) measurements revealed that the apparent θ decreased from partially hydrophobic (θ∼62°) to more hydrophilic (θ∼47°) when the corn starch was first added, leading to foams with a reduced stability. As the concentration of corn starch reached above ∼8vol.%, θ returned back to greater than 60°, rendering then a stable foam. On the other hand, θ was found to decrease from 57° to 50° when the agar concentration increased above a mere 0.16vol.%. This gave rise to a pronounced drainage and coalescence of the foam, and a further increase of the agar concentration only led to a quick disappearance of the a/w bubbles. By tailoring the binder concentration, macroporous gibbsite foams were produced from the air- or freeze-dried wet foams, which typically consisted of packing void cells over a cell-size distribution of 50–400μm, a porosity ranging from 77% to 86%, and a three-point (green) rupture strength of up to 240kPa.

The effect of fibrous fillers and metallic powders on the triboengineering characteristics of frictional composites based on the combined phenol-rubber binder

The findings of studies of the triboengineering characteristics of frictional composites based on the combined phenol-rubber binder filled with glass, basalt, carbon, and polyoxadiasol fibers and copper and iron powders are presented. The fibrous filler type and quality are found to influence the strength, friction, and wear characteristics of the composites. It is demonstrated that the composites filled with metallic powders have better thermal and physical characteristics.

Development of high-alumina ceramic concrete based on a composite binder

Information is provided for preparing high-alumina ceramic concretes based on a combined silicate-phosphate binder. Features are revealed for structure formation of the ceramic concrete developed during hardening, drying and firing; probable chemical reactions that occur are indicated.

(Invited) Greener and Cheaper Batteries Containing Fluorine-Free Binder in Combination with Ionic Liquid Based Electrolytes

The performance of LiFePO4-based electrode containing CMC as binder in combination with the ionic liquids N-butyl-N-methylpyrrolidinium bis(trifluoromethansulfonyl)imide (PYR14TFSI) and 1-ethyl-3-methyl-1-H-imidazolium bis(trifluoromethansulfonyl)imide (EMIMTFSI) have been evaluated at RT. The obtained results in term on the specific capacity and the cycling stability are reported in this manuscript.

Efecto de la adición mineral cal- zeolita sobre la resistencia a la compresión y la durabilidad de un hormigón

The international construction practice reports a remarkable use and development of high performance concretes, with excellent results in the durability properties, associated with a very dense cement matrix, defined from the use of high volumes of very fine minerals additions, such as, fly ash, silica fume, metakaolin and other fine powders. For the developing countries, among others Cuba, the use of these pozzolanic additions are relatively expensive, given for the high import prices of these pozzolanic materials, thus, the utility of using the national available pozzolanic sources with proven reactivity, as a partial substitute of the Ordinary Portland Cement (OPC) contents in the concrete mixtures without its properties are affected. The present paper shows the results of the study on the influence of substitution level of Ordinary Portland Cement contents by lime – pozzolan binder in combination with chemical admixture, in the behavior of the compression strength and the durability properties of a concrete. Several levels of OPC substitution are evaluated, using zeolite as pozzolan. The results obtained prove the possibility to carry out the partial replacement of high volumes of OPC by lime – zeolite binder, without affecting the values of compression strength required and their behavior before action of the chloride ion penetration and the carbonation.

Greener and Cheaper Batteries Containing Fluorine-free Binder in Combination with Ionic Liquid Based Electrolytes

not Available.

Strategies to manage low-bone turnover.

A change in paradigm occurred lately whereby not hypocalcemia but hypercalcemia and positive calcium balance were considered negative factors. Namely, the use of calcium- based binders in combination with vitamin D analogues, has been shown to lead to an over-suppression of parathyroid hormone (PTH) and development of low-bone turnover adynamic bone disease (ABD). The changing prevalence of various types of bone diseases from a high to low-bone turnover goes in line with the presence of increased risk for vascular calcification (VC), morbidity and mortality in the dialysis population. The attenuation of the previous great expectations in calcium-based phosphate binders and vitamin D-analogues entailed a new treatment strategy to preserve bone and vascular health. Hence, a new evidence for treatment of ABD with various types of non calcium based binders and low calcium dialysate is presented. Sevelamer treatment has reduced calcium concentration and increased PTH levels, resulting in the improvement of markers of bone turnover, increased bone formation and improved trabecular architecture, providing a slower progression of VC. Data on lanthanum beneficial effect on ABD histology have been demonstrated in long-term clinical studies. Although there is a slow release of lanthanum from its bone deposits after discontinuation of the treatment and no association with aluminium- like bone toxicity, there is still an ongoing scientific debate about its long-term toxic potential. Finally, reducing the number of calcium based binders and low calcium dialysate (1.25 mmol/l) has been reported to have an impact on the evolution towards markers reflecting higher bone turnover. Then, adoption of the non calcium-based binders should be reserved to high risk patients with ABD and progression of vascular calcifications associated with increased morbidity and mortality.

Influence of Binder Type on Interacting Variables Acting on Mechanical Properties of a Sulfadimidine Tablet Formulation

A study of the quantitative effect of type of binder (N), applied pressure (P), and granular size (G) on two mechanical properties–tensile strength (TS) and brittle fracture index (BFI)—of a sulfadimidine tablet formulation has been carried out by using a 23 factorial experimental design. The results obtained from this work suggest that P exhibited the largest individual effect on TS and BFI. It is also seen from this work that the nature of binders in combination affects the influence that P and G had on the TS or BFI.

Acoustical properties of aerated autoclaved concrete

This work analyses acoustic qualities of autoclaved aerated concrete (AAC). Three the most widely used types of AAC are chosen for the analysis: gas cement concrete, gas cement concrete with combined binder (Portland cement and lime), and foam cement concrete. The procedure and technique of the materials’ formation is presented in this work. The evaluation of acoustic qualities of AAC is based on the material’s air permeability and porosity (i.e., ratio of the volume of the interconnected pores to the total volume of pores). For this purpose the measurements obtained by an acoustic interferometer are used. The results of the experiment show that regression equations for the AAC types, which density ranges from 250 to 500 kg/m 3, may be used to estimate the materials’ normal incidence absorption coefficient values, which depend on the air permeability and porosity. Results show that absorption coefficient of not specially treated AAC is rather low. According to the measurements obtained in a special reverberation room of 202 m 3, a sound absorption coefficient may increase up to 0.6, provided that slits of Helmholtz resonator’s type are made in the slabs of AAC gas cement concrete with combined binder.

Circulating concentration of FGF-23 increases as renal function declines in patients with chronic kidney disease, but does not change in response to variation in phosphate intake in healthy volunteers

Hyperphosphatemia is a risk factor for the development of several different complications of chronic kidney disease (CKD), including secondary hyperparathyroidism and cardiovascular complications, due to the formation of calcium-phosphate deposits. Fibroblast growth factor-23 (FGF-23) is a recently discovered protein that is mutated in autosomal-dominant hypophosphatemic rickets, an inherited phosphate wasting disorder, and it may represent a novel hormonal regulator of phosphate homeostasis. We therefore hypothesized that FGF-23 levels may be altered in hyperphosphatemia associated with renal failure and that its concentration changes in response to different levels of phosphate intake. Using a two-site enzyme-linked immunosorbent assay (ELISA) detecting the C-terminal portion of FGF-23, serum concentration was measured in 20 patients with different stages of renal failure (creatinine range 155 to 724 micromol/L), in 33 patients with end-stage renal disease (ESRD) on dialysis treatment, and in 30 patients with functioning renal grafts. Furthermore, six healthy males were given oral phosphate binders in combination with low dietary phosphate intake for 2 days followed by 3 days of repletion with inorganic phosphate. FGF-23 levels were determined at multiple time points. FGF-23 serum levels were significantly elevated in CKD with a strong correlation between serum creatinine and FGF-23 concentration. Independent correlations were also seen between FGF-23 and phosphate, calcium, parathyroid hormone (PTH), and 1,25(OH)2D3. No changes in serum FGF-23 levels were observed in volunteers following ingestion of oral phosphate binders/low dietary phosphate intake, which led to a decline in phosphate excretion or during the subsequent repletion with inorganic phosphate through oral phosphate and a normal diet. Circulating FGF-23 was significantly elevated in patients with CKD and its concentration correlated with renal creatinine clearance. In healthy volunteers, FGF-23 levels did not change after phosphate deprivation or phosphate loading.

Formulation effects on the distribution of pigment particles in paints

Modern water-borne paints are widely used in different areas of applications ranging from high-gloss lacquers to flat, scrub-resistant interior paints. From this point of view, the pigment volume concentration (PVC) is one key-parameter adjusting the desired application properties. In high-gloss paints, for example, a low PVC is required to accommodate the proper surface roughness to achieve a high gloss. Consequently, a high concentration of TiO 2 is needed to obtain a good hiding power at the same time. Flat paints nonetheless are highly filled due to cost reasons preferentially by CaCO 3 and the pigment binding capacity of the binder is crucial. In this work, paint formulations differing in PVC, and the type of binder or dispersing agent were investigated by various techniques concerning the distribution and aggregation of pigment particles, e.g. TiO 2. To get a detailed insight into the structure of the liquid paints and the corresponding dried paint films, suitable analytical tools were applied for characterization. The structure of the liquid paints was analyzed by remission light spectroscopy (RLS), disc centrifugation, cryogenic-replication transmission electron microscopy (Cryo-replica TEM) and cryogenic-scanning electron microscopy (Cryo-SEM). The pigment distribution in the corresponding dried paint films was examined by means of atomic force microscopy (AFM), TEM and RLS. The tendency of the TiO 2-pigments to form aggregates was found to depend on both: first on the type of binder used in the formulation and second on the employed dispersing agent. It is shown that only by adjusting the properties of the binder in combination with common dispersants, it is possible to get well-distributed TiO 2 particles within the paint. Correlation of application properties, e.g. gloss and blocking to the microscopic structure is presented.

Investigation of melt agglomeration process with a hydrophobic binder in combination with sucrose stearate.

The melt agglomeration process of lactose powder with hydrogenated cottonseed oil (HCO) as the hydrophobic meltable binder was investigated by studying the physicochemical properties of molten HCO modified by sucrose stearates S170, S770 and S1570. The size, size distribution, micromeritic and adhesion properties of agglomerates as well as surface tension, contact angle, viscosity and specific volume of molten HCO, with and without sucrose stearates, were examined. The viscosity, specific volume and surface tension of molten HCO were found to be modified to varying extents by sucrose stearates which are available in different HLB values and melt properties. The growth of melt agglomerates was promoted predominantly by an increase in viscosity, an increase in specific volume or a decrease in surface tension of the molten binding liquid. The agglomerate growth propensity was higher with an increase in inter-particulate binding strength, agglomerate surface wetness and extent of agglomerate consolidation which enhanced the liquid migration from agglomerate core to periphery leading to an increased surface plasticity for coalescence. The inclusion of high concentrations of completely meltable sucrose stearate S170 greatly induced the growth of agglomerates through increased specific volume and viscosity of the molten binding liquid. On the other hand, the inclusion of incompletely meltable sucrose stearates S770 and S1570 promoted the agglomeration mainly via the reduction in surface tension of the molten binding liquid with declining agglomerate growth propensity at high sucrose stearate concentrations. In addition to being an agglomeration modifier, sucrose stearate demonstrated anti-adherent property in melt agglomeration process. The properties of molten HCO and melt agglomerates were dependent on the type and concentration of sucrose stearate added.